// Copyright 2015 go-swagger maintainers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package client

import (
	"bytes"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"mime/multipart"
	"net/http"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"strings"
	"time"

	"github.com/go-openapi/runtime"
	"github.com/go-openapi/strfmt"
)

// NewRequest creates a new swagger http client request
func newRequest(method, pathPattern string, writer runtime.ClientRequestWriter) (*request, error) {
	return &request{
		pathPattern: pathPattern,
		method:      method,
		writer:      writer,
		header:      make(http.Header),
		query:       make(url.Values),
		timeout:     DefaultTimeout,
	}, nil
}

// Request represents a swagger client request.
//
// This Request struct converts to a HTTP request.
// There might be others that convert to other transports.
// There is no error checking here, it is assumed to be used after a spec has been validated.
// so impossible combinations should not arise (hopefully).
//
// The main purpose of this struct is to hide the machinery of adding params to a transport request.
// The generated code only implements what is necessary to turn a param into a valid value for these methods.
type request struct {
	pathPattern string
	method      string
	writer      runtime.ClientRequestWriter

	pathParams map[string]string
	header     http.Header
	query      url.Values
	formFields url.Values
	fileFields map[string][]runtime.NamedReadCloser
	payload    interface{}
	timeout    time.Duration
	buf        *bytes.Buffer
}

var (
	// ensure interface compliance
	_ runtime.ClientRequest = new(request)
)

func (r *request) isMultipart(mediaType string) bool {
	if len(r.fileFields) > 0 {
		return true
	}

	return runtime.MultipartFormMime == mediaType
}

// BuildHTTP creates a new http request based on the data from the params
func (r *request) BuildHTTP(mediaType, basePath string, producers map[string]runtime.Producer, registry strfmt.Registry) (*http.Request, error) {
	return r.buildHTTP(mediaType, basePath, producers, registry, nil)
}

func (r *request) buildHTTP(mediaType, basePath string, producers map[string]runtime.Producer, registry strfmt.Registry, auth runtime.ClientAuthInfoWriter) (*http.Request, error) {
	// build the data
	if err := r.writer.WriteToRequest(r, registry); err != nil {
		return nil, err
	}

	if auth != nil {
		if err := auth.AuthenticateRequest(r, registry); err != nil {
			return nil, err
		}
	}

	// create http request
	var reinstateSlash bool
	if r.pathPattern != "" && r.pathPattern != "/" && r.pathPattern[len(r.pathPattern)-1] == '/' {
		reinstateSlash = true
	}
	urlPath := path.Join(basePath, r.pathPattern)
	for k, v := range r.pathParams {
		urlPath = strings.Replace(urlPath, "{"+k+"}", url.PathEscape(v), -1)
	}
	if reinstateSlash {
		urlPath = urlPath + "/"
	}

	var body io.ReadCloser
	var pr *io.PipeReader
	var pw *io.PipeWriter

	r.buf = bytes.NewBuffer(nil)
	if r.payload != nil || len(r.formFields) > 0 || len(r.fileFields) > 0 {
		body = ioutil.NopCloser(r.buf)
		if r.isMultipart(mediaType) {
			pr, pw = io.Pipe()
			body = pr
		}
	}
	req, err := http.NewRequest(r.method, urlPath, body)

	if err != nil {
		return nil, err
	}

	req.URL.RawQuery = r.query.Encode()
	req.Header = r.header

	// check if this is a form type request
	if len(r.formFields) > 0 || len(r.fileFields) > 0 {
		if !r.isMultipart(mediaType) {
			req.Header.Set(runtime.HeaderContentType, mediaType)
			formString := r.formFields.Encode()
			// set content length before writing to the buffer
			req.ContentLength = int64(len(formString))
			// write the form values as the body
			r.buf.WriteString(formString)
			return req, nil
		}

		mp := multipart.NewWriter(pw)
		req.Header.Set(runtime.HeaderContentType, mangleContentType(mediaType, mp.Boundary()))

		go func() {
			defer func() {
				mp.Close()
				pw.Close()
			}()

			for fn, v := range r.formFields {
				for _, vi := range v {
					if err := mp.WriteField(fn, vi); err != nil {
						pw.CloseWithError(err)
						log.Println(err)
					}
				}
			}

			defer func() {
				for _, ff := range r.fileFields {
					for _, ffi := range ff {
						ffi.Close()
					}
				}
			}()
			for fn, f := range r.fileFields {
				for _, fi := range f {
					wrtr, err := mp.CreateFormFile(fn, filepath.Base(fi.Name()))
					if err != nil {
						pw.CloseWithError(err)
						log.Println(err)
					}
					if _, err := io.Copy(wrtr, fi); err != nil {
						pw.CloseWithError(err)
						log.Println(err)
					}
				}
			}

		}()
		return req, nil

	}

	// if there is payload, use the producer to write the payload, and then
	// set the header to the content-type appropriate for the payload produced
	if r.payload != nil {
		// TODO: infer most appropriate content type based on the producer used,
		// and the `consumers` section of the spec/operation
		req.Header.Set(runtime.HeaderContentType, mediaType)
		if rdr, ok := r.payload.(io.ReadCloser); ok {
			req.Body = rdr

			return req, nil
		}

		if rdr, ok := r.payload.(io.Reader); ok {
			req.Body = ioutil.NopCloser(rdr)

			return req, nil
		}

		req.GetBody = func() (io.ReadCloser, error) {
			var b bytes.Buffer
			producer := producers[mediaType]
			if err := producer.Produce(&b, r.payload); err != nil {
				return nil, err
			}

			if _, err := r.buf.Write(b.Bytes()); err != nil {
				return nil, err
			}
			return ioutil.NopCloser(&b), nil
		}

		// set the content length of the request or else a chunked transfer is
		// declared, and this corrupts outgoing JSON payloads. the content's
		// length must be set prior to the body being written per the spec at
		// https://golang.org/pkg/net/http
		//
		//     If Body is present, Content-Length is <= 0 and TransferEncoding
		//     hasn't been set to "identity", Write adds
		//     "Transfer-Encoding: chunked" to the header. Body is closed
		//     after it is sent.
		//
		// to that end a temporary buffer, b, is created to produce the payload
		// body, and then its size is used to set the request's content length
		var b bytes.Buffer
		producer := producers[mediaType]
		if err := producer.Produce(&b, r.payload); err != nil {
			return nil, err
		}
		req.ContentLength = int64(b.Len())
		if _, err := r.buf.Write(b.Bytes()); err != nil {
			return nil, err
		}
	}

	if runtime.CanHaveBody(req.Method) && req.Body == nil && req.Header.Get(runtime.HeaderContentType) == "" {
		req.Header.Set(runtime.HeaderContentType, mediaType)
	}

	return req, nil
}

func mangleContentType(mediaType, boundary string) string {
	if strings.ToLower(mediaType) == runtime.URLencodedFormMime {
		return fmt.Sprintf("%s; boundary=%s", mediaType, boundary)
	}
	return "multipart/form-data; boundary=" + boundary
}

func (r *request) GetMethod() string {
	return r.method
}

func (r *request) GetPath() string {
	path := r.pathPattern
	for k, v := range r.pathParams {
		path = strings.Replace(path, "{"+k+"}", v, -1)
	}
	return path
}

func (r *request) GetBody() []byte {
	if r.buf == nil {
		return nil
	}
	return r.buf.Bytes()
}

// SetHeaderParam adds a header param to the request
// when there is only 1 value provided for the varargs, it will set it.
// when there are several values provided for the varargs it will add it (no overriding)
func (r *request) SetHeaderParam(name string, values ...string) error {
	if r.header == nil {
		r.header = make(http.Header)
	}
	r.header[http.CanonicalHeaderKey(name)] = values
	return nil
}

// SetQueryParam adds a query param to the request
// when there is only 1 value provided for the varargs, it will set it.
// when there are several values provided for the varargs it will add it (no overriding)
func (r *request) SetQueryParam(name string, values ...string) error {
	if r.query == nil {
		r.query = make(url.Values)
	}
	r.query[name] = values
	return nil
}

// GetQueryParams returns a copy of all query params currently set for the request
func (r *request) GetQueryParams() url.Values {
	var result = make(url.Values)
	for key, value := range r.query {
		result[key] = append([]string{}, value...)
	}
	return result
}

// SetFormParam adds a forn param to the request
// when there is only 1 value provided for the varargs, it will set it.
// when there are several values provided for the varargs it will add it (no overriding)
func (r *request) SetFormParam(name string, values ...string) error {
	if r.formFields == nil {
		r.formFields = make(url.Values)
	}
	r.formFields[name] = values
	return nil
}

// SetPathParam adds a path param to the request
func (r *request) SetPathParam(name string, value string) error {
	if r.pathParams == nil {
		r.pathParams = make(map[string]string)
	}

	r.pathParams[name] = value
	return nil
}

// SetFileParam adds a file param to the request
func (r *request) SetFileParam(name string, files ...runtime.NamedReadCloser) error {
	for _, file := range files {
		if actualFile, ok := file.(*os.File); ok {
			fi, err := os.Stat(actualFile.Name())
			if err != nil {
				return err
			}
			if fi.IsDir() {
				return fmt.Errorf("%q is a directory, only files are supported", file.Name())
			}
		}
	}

	if r.fileFields == nil {
		r.fileFields = make(map[string][]runtime.NamedReadCloser)
	}
	if r.formFields == nil {
		r.formFields = make(url.Values)
	}

	r.fileFields[name] = files
	return nil
}

// SetBodyParam sets a body parameter on the request.
// This does not yet serialze the object, this happens as late as possible.
func (r *request) SetBodyParam(payload interface{}) error {
	r.payload = payload
	return nil
}

// SetTimeout sets the timeout for a request
func (r *request) SetTimeout(timeout time.Duration) error {
	r.timeout = timeout
	return nil
}
